This invention relates to an electrical control apparatus for use in receiving input data from a plurality of separate sources and providing a plurality of outputs to separate controlled elements based upon a predetermined program, wherein the apparatus includes a plurality of separate control modules communicating on a connecting bus, and particularly to an improvement in which the modules can be readily replaced in the event of failure.
Control apparatus for controlling electrical systems for various end uses are well known and widely required. The present invention is particularly but not exclusively concerned with such control apparatus for use in vehicles such as trucks, trains, boats, aircraft and passenger transit vehicles. However devices of this type can also be used for controlling industrial processes.
A vehicle such as a passenger transit vehicle has a large number of electrical inputs from operator actuated switches and from various other transducers such as temperature sensors and door closure switches. The vehicle further has a large number of electrical outputs where various components such as lighting, air conditioning, door actuators and engine control systems require output at a predetermined voltage from the power system of the vehicle.
One conventional arrangement for controlling the various outputs from the various inputs includes a plurality of control modules which are interconnected by a communication bus.
Each module has a series of input terminals for receiving control signals from a selected combination of the various inputs of the system. Each module has a plurality of outputs for supplying output voltage to selected ones of the series of controlled elements of the system. Each module has a plurality of switches which can be actuated to supply output as required to one or more of the output terminals. The switches are controlled by a processor in the module. The switches are preferably electronic but other electromechanical switches can be used in some cases. The module has a communications connection for two way communication between the processor and the communication bus so that the status of the module can be communicated onto the communication bus and so that information concerning the other modules can be communicated from the communication bus to the processor.
The modules are programmed with the necessary program to effect the function of each of the modules so that the modules are in effect identical and each can carry out the function of the others. This ensures that replacement modules for use in the event of a failure of one of the modules can simply be taken from a supply of the modules and can carry out whichever function is required of that particular module. An input arrangement provided by one or more conductors is provided for communicating to the module which function it is to undertake when installed in the vehicle.
The modules are programmable to provide a base program which carries out the basic functioning of the module and to receive an operating program relating to the functions of the modules.
It will of course be appreciated that the vehicles manufactured by a particular manufacturer using this system vary over the years as modifications are introduced and also may vary at any particular time due to different options and different configurations of the vehicles be manufactured.
The modules therefore must be programmed with the particular configuration of vehicle with which the module is to be used thus requiring an inventory of replacement modules dedicated to the particular vehicles concerned.
It is one object of the present invention therefore to provide an improved apparatus which avoids or reduces the necessity for an inventory of modules dedicated to different system configurations.
According to one aspect of the invention there is provided a control apparatus comprising:
a plurality of sources of input signals;
a plurality of controlled elements;
a communication bus;
and a plurality of separate control modules each having:
connection to the communication bus for transmitting communications on and receiving communications from the bus;
a plurality of input terminals arranged for receiving at least one input from a respective one of said plurality of sources of input signals;
a plurality of output terminals at least one of which is arranged for connection to a respective one of the controlled elements;
a plurality of switches each associated with a respective one of the output terminals for effecting control of the respective controlled element;
a processor programmable so as to actuate the switches in response to data from the input terminals and in response to said communications on the communication bus in accordance with a predetermined program stored in the module;
the modules each having a different function such that each receives input from a different one or more of the sources of input data and each effects control of a different one or more of the controlled elements;
wherein said predetermined program is the same in each of the modules and includes a base program and an operating program portion having respective sub-portions thereof with each sub-portion arranged to control the function of the respective module in which the program is stored;
and wherein the modules and the predetermined program therein are arranged such that, at a predetermined condition of the apparatus, the processor of each module emits to the communication bus a signal indicative of the operating program portion stored in the respective module, such that there is effected a comparison of the emitted signals, and such that, in the event that the emitted signal of one of the modules is different from that of the others, a selected one of the others is arranged to download the operating program portion from said selected one to said different one.
Preferably all of the modules are substantially identical and wherein each module has an input for determining which of the functions of the modules is applicable to that module. It is preferred to provide identical modules since this provides the best efficiency for inventory control. However in some cases, the modules may have different hardware configurations for effecting different functions, but contain the same base software for running the basic programs as described hereinafter and the same operating program programmed in the manner of the present invention and described herein.
Preferably the emitted signal comprises a reference number included in the operating program portion and identifying the operating program portion. This can be supplemented by an optional check sum calculated from the operating program portion to ensure checking of accuracy.
Preferably the apparatus includes a port connected to the communication bus for receiving programming information on the communication bus for simultaneously programming all of the modules with said operating program portion.
Preferably the predetermined condition is arranged to occur at an initial power-up of the apparatus.
Preferably each of the modules is arranged to be in an operating condition only in the event that it is receiving an input on one or more of a selected number of the input terminals thereof and wherein the predetermined condition is arranged such that each of the modules is receiving an input to said selected number of input terminals thereof such that each is in the operating condition.
Preferably the inputs to each module are arranged so that the predetermined condition only occurs at a power-up and only in the event that each of the modules is receiving an input to said selected ones of input terminals thereof.
Preferably the predetermined program is arranged, in the event that the emitted signal of one of the modules is different from that of the others, to select a particular one of the modules to download the operating program portion unless the particular one is the different one in which case selects another one of the modules is selected.
Preferably the selected one downloads the operating program portion in a plurality of separate sections of program each including a check sum.
Preferably the control apparatus is provided in a vehicle for controlling electrical components of the vehicle and in such a case, the modules may be located at different locations in the vehicle including at least one at the front, at least one at the rear and at least one at an intermediate location along the length thereof.
Preferably a first one of the modules is connected to a source of 12 vDC voltage and is arranged to control the switches thereof to provide the 12 vDC voltage as a high side output at least at some of the outputs thereof for supply to the controlled elements and a second one of the modules is connected to a source of 24 vDC voltage and is arranged to control the switches thereof to provide the 24 vDC voltage as a high side output at least at some of the outputs thereof for supply to the controlled elements. More preferably each module has two rails or input bars each of which can be supplied with either 12 vdc or 24 vdc, so that both rails are of the same voltage or each is of a different voltage depending upon the output requirements. Each module is preferably powered by a logic voltage which is either 24 v or 12 v depending upon the convenience of the system.
Preferably at least one of the first and second modules includes at least one further output arranged to be connected by a respective one of the switches, which is bi-directional, to ground such that said one further output provides a low side output.
Preferably each module includes a set of input status LEDs and a set of output status LEDs and wherein each input is associated with a respective one of the input LEDs and each output is associated with a respective one of the output LEDs and wherein the input LEDs are arranged to be on when an input is present and to be off when no input is present and wherein the output LEDs are arranged to be on when an output is present and to be off when no output is present and to flash when a fault is present on the output.
Preferably there is provided a diagnostic harness arranged to provide a feedback connection from respective ones of the output to respective ones of the inputs.
Preferably each module is arranged to provide a power save mode wherein the module goes power-off except when an input is provided to selected ones of the inputs thereto.
According to a second aspect of the invention there is provided a method of replacing a module in a control apparatus as defined above wherein the method comprises:
replacing one of the modules with a replacement module;
after replacement, at a predetermined condition of the apparatus, causing the processor of each module to emit to the communication bus a signal indicative of the operating program portion stored in the respective module;
causing the modules to effect a comparison of the emitted signals;
and, in the event that the emitted signal of one of the modules is different from that of the others, causing a selected one of the others to download the operating program portion from said selected one to said different one.
According to a third aspect of the invention there is provided an individual module for use in a system of the type defined above arranged by the program stored therein to effect the steps set forth in the method above when connected into the apparatus.